This invention relates to apparatus for processing frozen blood in the course of reconstituting it fro infusion to a recipient. More particularly the invention provides improvements in apparatus for washing from red blood cells an additive introduced to preserve the cells during frozen storage.
Red blood cells frozen with a protective additive must be washed clean of the additive prior to resuspending the cells in plasma for subsequent infusion. The present invention effects the washing of the red blood cells within a closed, pliable, bag-like wash-container by means of a known technique that employs wash liquids having properties such that the cells when undisturbed tend to agglomerate and settle, rather than remain suspended in the liquid. This in turn makes it possible to decant the spent wash liquid from the agglomerated red cells. The result is that the spent wash liquid can be separated readily and quickly from the cells with minimal loss of cells and with maximal removal of spent liquid from the cells. U.S. Pat. No. 3,351,432, including the references cited therein, discloses this cell washing technique in further detail and discloses one apparatus for performing it.
The prior cell washing apparatus of that patent, however, has shortcomings which the instrument of this invention resolves. Specifically, the prior cell washing apparatus requires considerable vertical height to suspend the elongated wash container. For example, one device constructed according to the prior techniques for bench top insulation requires that a hole be cut through the bench top to provide vertical space in which to suspend the container.
The wash container has considerable length to provide a punch at one end for containing the red cells during the washing process, and to provide at the other end a bladder for receiving and containing successive applications of spent wash liquid. The container also has a medial section through which the wash liquid is transferred from the pouch portion to the bladder portion. Although the container in most instances does not have structure demarking such separate portions, it is convenient to consider the overall container structure as providing these portions for ease in explaining the invention.
The container typically is draped over a roller-like gate at the medial section with the cell-containing pouch depending on one side and the bladder depending on the other side. This known disposition of the container maintains the medial section under tension over the roller gate. This ensures that the gate provides the desired liquid barrier between the pouch and the bladder portions. The suspension of the container from the roller gate further ensures that the container is fully unfurled.
Prior art wash apparatus also is difficult to operate entirely by hand, and hence employs a motor drive to raise and lower the bag-suspending gate. This, however, has proven to result in relatively costly, cumbersome and noisy apparatus and does not readily allow facile manual control of the position of the gate.
Accordingly, it is an object of this invention to provide red blood cell washing apparatus having an improved mechanism for maintaining the wash container deployed under tension.
A further object is to provide red cell washing apparatus that requires significantly less vertical height than prior devices of this kind for deploying the wash container.
Another object is to provide red cell washing apparatus readily capable of direct manual operation.
Still another object of the invention is to provide apparatus of the above character that is relatively compact, that is relatively low cost to fabricate, and that provides ready access to the mechanisms thereof.
Other objects of the invention will in part be obvious and will in part be set forth hereinafter.